This invention relates to a doorway system that allows the use of taller than standard size glass doors and a novel form of header that is used to hold glass doors and sidelight panels in an entranceway. More specifically, the invention relates to glass doors and sidelight panels of a designer's choice of size that are made of glass, or similar materials, and that can be easily erected, inside or outside a building and which allow the doors to be easily moved if repairs are needed.
Architects and building designers are making more and more use of glass doors and sidelights when creating modern buildings. Current design methods attempt to use tall glass doors and sidelights, such as ones that reach from the floor to a twelve-foot high ceiling. Up until the present invention, designers have tended to avoid using glass doors that are taller than the standard eight foot height because of the special construction techniques, and need for 3/4 inch glass to provide door stiffness, and hence, extra expense, that would be required. Once the height of a 1/2 inch thick glass door becomes higher than eight feet, the weight, deflection and physical size of the door become factors that require special consideration in the areas of installation of the door and of making repairs to the closer mechanism or other areas around the door once it has been installed. It is desirable to use 1/2 inch thick glass because it can be tinted, such as with a bronze or gray color.
Tempered glass of 1/2 inch thickness weighs approximately 6.56 pounds per square foot and standard doors, of approximately eight foot height by three foot width, weigh about 160 pounds (plus the weight of the hardware used to attach the door). This weight is almost doubled, to about 315 pounds (plus hardware weight), if the door is twelve feet high by four feet wide, and that makes it heavier for the installers to handle and much more awkward to move around during installation. In addition, as the height of the door increases above eight feet, door deflection increases with wind load. Patch fittings that attach the door and transom glass to the sidelight put more strain on the sidelight, thus the sidelights have to be made thicker or glass fins (both of which increase the cost) added to prevent massive deflection of the sidelight under wind-load. Outdoor wind-load design requirements around the United States average 20 pounds per square foot of force and indoor wind-load design requirements average 5 pounds per square foot of force. While the deflection that results from this required wind-load is not necessarily a safety problem, it is an aesthetic problem that detracts from the building's appearance.
It is also known that office building doors use hydraulic door closer mechanisms, such as those made by the Dorma Rixxon and Door-o-Matic Companies, that sit in the floor at the corner of the doorsill to control closing movement of the door. These mechanisms are typically enclosed in a box under the surface of the floor and have only a spindle projecting upward through the door threshold adjacent the door frame. With standard doors, this spindle will bear all of the door weight and it is necessary for the work crew to align the door with the doorway framework at the construction site so that the vertical edge is correctly set over the spindle.
Also, with standard hardware and construction techniques, it is very difficult to make repairs to the door closer mechanism once a tall door is erected over it. Two more factors now become important: how strong are the side panels and transom, for they have to bear the weight of the heavier than normal door, and how strong is the closer mechanism, because it must restrict the closing movement of the heavy door. With the current methods and doorway structure, if any repairs to the closer mechanism become necessary, the complete door must be removed, not just slid back from the edge of the closer and this entails a large amount of effort.